Fan support base



FIG. 1 is a front and right side perspective view of a fan support base showing our new design;

FIG. 2 is a rear perspective view thereof; and,

FIG. 3 is a left side perspective view thereof.

The broken line showing of a fan in FIGS. 1-3 is for illustrative purposes only, and forms no part of the claimed design. The bottom of the fan support base is flat and unornamented. 

The ornamental design for a fan support base, as shown and described. 